Telegraph circuit



A.VVEAVER TELEGRAPH CIRCUIT Filed Jan. 19, 1924 HVVENTOR gm ATTORNEYPatented Jan. 12, 1926.

UNITED STATES 1,569,955 PATENT OFFICE.

ALLAN WEAVER, F BROOKLYN NEVJ YORK, ASSIGNOR TO AMERICAN TELEPHONE ANDTELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

TELEGRAPH CIRCUIT.

Application filed January 19,1924.

To all whom it may concern:

Be it known that I, ALLAN \Vnnvnn, residing at Brooklyn, in the countyof Kings and State of New York, have invented certain Improvements inTelegraph Circuits, of which the following is a specification.

This invention relates to telegraph systems and more particularly tobreaking arrangements for such systems.

In telegraph systems, such for example as half duplex systems, it isoften desirable for an operator at a station at which signals are beingreceived to be able to send .a break signal to interrupt the sendingoperator at the distant station in order to gain control of the line.This is generally accomplished by opening the local loop circuit andthus causing the armature of the sending relay to move to its spacingcontact, while at the same time preventing the sending relay from beingoperated ,or affected by the action of the receiving relay caused by theincoming signals. The arrangements of this invention provide improvedarrange- 26 ments for this purpose. Other objects and features of theinvention will appear more fully from the detailed descriptionhereinafter given.

The invention may be more fully under- 80 stood from the followingdescription together with the accompanying drawing, in which isillustrated a circuit diagram of a telegraph station embodying theinvention.

In the drawing is shown an incoming line L terminating at a station inthe polar receiving relay RR. Associated with the armature of thereceiving relay RR are the marking and spacing contacts M and S, withwhich are associated the oppositely poled marking and spacing batteries4 and 5 respectively. Connected to the armature of the receiving relayRR is a branched loop circuit 1, 2. The loop circuit includes thewindings of a polar break relay BR and a polar sending relay SR. One endof the loop circuit will terminate in the artificial line AL and theother end of the loop circuit may include a key K, a sounder S and thebattery 3. The loop circuit is associated with the armature of thereceiving relay so that with the key closed the wind ings of the polarbreak relay and the windings of the sending relay will balance eachother and will not be affected by the receiving relay armature.Controlled by the Serial No. 637,362.

sending relay SR is a pole changing device 9, connected with a line Lwhereby signals may be transmitted to a distant station. An armature andmarking and spacing contacts M and S are provided for the break relayBR. The armature of .the break relay is connected by conductor 7 toconductor 1 of the loop circuit and may include a resistance 8. Thespacing contact of the break relay is connected by conductor 6 to thenegative pole of battery l associated with the marking contact of thereceiving relay. When the subscriber at this station wishes to break orinterrupt the distant operator transmitting signals over the line L tothe station, the key K will be opened. When the key K is opened thebreak relay. 'B'R will move its armature from its marking contact to itsspacing contact. With the key K closed positive battery 3 would normallybe applied to the windings of the relays BR and SR and through theartificial line to ground. However, when the key K is opened and thebreak relay BR movesits armature to its spacing contact, negativebattery will be put on the relay windings in place of the positivebattery from the subscribers loop in the following manner: from ground,negative battery t, conductor 6, spacing contact and armature v01 breakrelay BR, resistance 8, conductor 7, conductor l, windings of breakrelay BR and sending relay SR, over conductor 2, artificial line AL, toground. If, at this time, the armature of the receiving relay is on itsno marking contact no current will flow in the upper windings of thesending relay and break relay but a current will flow from battery 4through the lower windings of the sending relay and the break relay tothe artificial line and ground in such a direction as to cause therelays to maintain their armatures on their spacing contacts. If thearmature of the receiving relay should now move to its spacing contactthe current in the lower windings of the break relay and sending relaywould be reversed, tending to cause these relays to move their armaturesto their marking contacts. However, a current will at the same time flowin the 106 upper windings of these relays as follows: from ground andpositive battery 5, spacing contact and armature of receiving relay RR,

the upper windings of sending relay SR and break relay BR, conductor 1,conductor 7, no;

resistance 8, armature and spacing contact the battery 5 will be appliedto the circuit through the lower windings of the brealr relay andsending relay the current flow in the upper windings will be greaterthan that in the lower windings by an amount sufficient to hold thearmatures of these relays on their spacing contacts. Accordingly, aspacing signal will be sent out over the line L, regardless of thesignal received at relay RR. lVhen the subscriber in the loop circuit isreceiving, the armature of the break relay BR, as has been pointed out,will be on its marking contact M. The duplex balance of the loop circuit1, 2 will accordingly not be affected as the marking contact of thebreak relay is open.

Certain of the advantages of the arrangements of the invention consistin. the fact that only low voltages are applied to the contacts of thebreak relay. No additional contacts other than those of the receivingrelay in the main grounded line circuits are needed, and only one of thetwo contacts on the break relay are utilized, which accordingly makesthe requirements of this relay less severe than in other instances.lVhilethe invention has been disclosed in certain specific arrangementswhich are deemed desirable it is to be understood that it is capable ofembodiment in many and widely varied forms without departing from thespirit of the invention as defined in the appended claims. i

What is claimed is:

1. A telegraph system comprising a receiving relay, an armaturetherefore, marking and spacing contacts associated with said armature,marking and spacing batteries associated with said contacts, a branchedloop circuit connected to said armature, windings in each branch of saidloop circuit of a polar break relay and of a will be included polarsending relay, an armature for said break relay, marking and spacingcontacts or said break relay, means for connecting the armature of saidbreak relay to the upper brancl'i of said loopcircuit, and means forconnecting the spacing contact of said break relay to the markingbattery of said receiving relay.

2. A-telegraph system comprising a receiving relay, an armaturetherefore, marking and spacing contacts associated with said armature,marking and spacing batteries as sociated with said contacts, a branchedloop circuit connected to said armature, windings in each branch of saidloop circuit of a polar break relay and of a polar sending relay, anarmature for said break relay, marking and spacing contacts for saidbreak relay, the windings of said break relay being so poled that whensaid loop circuit is opened the armature of said break relay will reston its spacing contact, means for connecting the armature of? said breakrelay to the upper branch of said loop circuit, and means for connectingthe spacing contact of said break relay to the marking battery of saidreceiving relay.

3. A telegraph system comprising a receiving relay, anarmaturetherefore, marking and spacing contacts associated with saidarmature, marking and spacing batteries associated with said contacts, abranched loop circuit connected to said armature, windings in eachbranch ofsaid loop circuit 01 a polar break relay and a polar sendingrelay, and means controlled by said break relay for applying currentfrom said marking and spacing batteries to said relay windings in saidloop circuit in such directions that said relays will hold theirarmatures on their spacing contacts regardless of the position of thearmature oil said receiving relay. 7

In testimony whereof, I have signed my name to this specification this16th day of January 1924. ,j

ALLAN WEAVER.

